1. Field of the Invention
This invention relates to body washes based on aqueous preparations of water-soluble surfactants in which lipid-soluble cosmetic or pharmaceutical active substances are incorporated in a manner which ensures increased absorption of the active substances into the skin during the washing process.
2. Discussion of Related Art
It is known that cosmetic or dermatological agents can be added to body washes in order to exert a dermatologically favorable or cosmetically desirable influence on the condition of the skin during the washing process.
Hitherto, however, only water-soluble active substances have been suitable for this purpose because it is only water-soluble active substances which come into contact with the skin sufficiently to develop an effect in the relatively short time taken by the washing process. Although attempts have been made to incorporate oil-soluble active substances in water-based body washes by emulsification or solubilization, the resulting effects on the skin were not satisfactory because the active substances were either encapsulated in emulsion droplets or solubilized in surfactant micelles.
Accordingly, attempts have been made to find ways of incorporating lipid-soluble active substances in a homogeneous and stable manner in water-based body washes and, at the same time, to achieve improved penetration of the active substances during the relatively short contact time with the skin. As a result of these various attempts, it was found that improved skin penetration can be achieved if the active substances in question are present as a component in lipid/surfactant mixed micelles, lipid microemulsions or wax nanoparticles with an average particle size below 500 nm.